Apparatus for feeding sheets of paper

ABSTRACT

Apparatus for feeding sheets cut from a continuous web of paper in an underlapping sequence or array comprising a group of suction cups, suction rollers or the like, which are adapted to be moved back and forth parallel to the line of travel of the sheets and attach themselves to the trailing edges of successive sheets after they are freed from conveying means to lift the edges of these sheets, retard their forward movement, and stretch the sheets in such a manner that the leading edge of the next sheet is moved below the raised edge.

ilnited States Patent [191 Spiess [451 May 1, i973 1 1 APPARATUS FOR FEEDING SHEETS OF PAPER [76] Inventor: Helmit Spiess, I-laydnstrasse 17a,

8906 Gersthoffen,- Gemiany [22] Filed: Feb. 11, 1971 [21] App]. No.: 114,623

[30] Foreign Application Priority Data Mar. 5, 1970 Germany ..P 20 10467.0

[52] US. Cl ..271/46, 271/76, 27l/DIG. 4 [51] Int. Cl. ..B65h 5/24 [58] Field of Search ..271/74, DIG. 8, DIG. 4,

[56] References Cited UNITED STATES PATENTS Geigenmiller et a1 ..271/76 UX 2,285,076 6/1942 Backhouse ..271/46 1,994,012 3/1935 Broadmeyer ..271/D1G. 4 1,545,912 7/1925 Maxson ..271/DlG. 8

Primary Examiner-Richard E. Aegerter Assistant Examiner-Bruce H. Stoner, Jr. Att0rneyH. Geoffrey Lynfield 5 7 ABSTRACT Apparatus for feeding sheets cut from a continuous web of paper in an underlapping sequence or array comprising a group of suction cups, suction rollers or the like, which are adapted to be moved back and forth parallel to the line of travel of the sheets and attach themselves to the trailing edges of successive sheets after they are freed from conveying means to lift the edges of these sheets, retard their forward movement, and stretch the sheets in such a manner that the leading edge of the next sheet is moved below the raised edge.

1 Claim, 5 Drawing Figures PATENTEI] HAY 1 i975 SHEET 1 BF 3 APPARATUS FOR FEEDING SHEETS OF PAPER The invention relates to sheet feeders comprising separating and conveying means for separating the sheets and conveying the same to a machine for further processing said sheets such as a printing machine.

The object of the invention is to provide a sheet feeder in which a paper web cutter is used but which obviates the use ofa turnover drum and a device which overlaps the individual sheets, the sheets separated from the web being fed to the feed table with their longitudinal edges forward. The cutter is also intended to perform only as many cuts per unit of time as sheets are to be fed to the sheet-using machine per unit of time.

Another object of the invention is to so construct the sheet feeder that it can selectively be changed over in a short period of time and without any appreciable conversion to handling webs or sheet piles on a raisable pile table.

According to the invention I provide apparatus for feeding sheets cut from a continuous web of paper in an underlapping sequence or array comprising a group of suction cups, suction rollers or the like which are adapted to be moved back and forth parallel to the line of travel of the sheets and attach themselves to the trailing edges of successive sheets after they are freed from conveying means to lift the edges of these sheets, retard their forward movement, and stretch the sheets in such a manner that the leading edge of the next sheet is moved below the raised edge.

Further details ofthe invention will be apparent from the following description ofa preferred embodiment illustrated in the accompanying drawings, wherein:

FIG. 1 is a diagrammatic side elevation of the sheet feeder;

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a vertical cross-section taken on lines III III in FIG. 1 through the support on which the underlapping sheets are guided;

FIG. 4 is a similar view of the support in a different adjustment; and

FIG. 5 shows a view similar to FIG. 1, the frame carrying the head stop and conveyor section having been lowered and moved to the right underneath the middle conveyor section.

In the example illustrated in FIGS. 1 to 4, the web of paper is unreeled from a reel a and is fed to a cross cutter b which cuts the web into sheets of adjustable length. Conveyor belts c, and 0 receiving the sheets move at greater speed so as to create some gaps between the individual sheets. As soon as the rear end ofa sheet has been released by the left-hand rollers dof the top belt 0,, the sheet end is engaged by pneumatically or mechanically controlled suction cups e, suction roller of the like is lifted and retarded in respect of its further movement. At the same time, the leading edge of the sheet passes between rollers f and the bottom belt rollers 11 around which belts g extend and which rotate at a reduced speed, and further transport the brake sheet at a lower speed.

Since the sheet is for the time being retained at its rear edge by the suction cups 2, it is stretched and lifted from the bottom belts 0 Consequently, the next following sheet which is still located between belts c and c and is moving at greater speed, passes with its forward edge without obstruction beneath the rear edge of the leading sheet moving at lower speed so that an array of underlapping sheets is formed.

The suction cups e are so disposed that, although they follow the slow forward movement of the engaged sheet, they offer some resistance to this movement of the sheet, for instance, by spring tension. Consequently the sheet remains stretched as long as its rear end is engaged by the suction cups e. When the suction cups e have covered the short distance as indicated by the shorter arrowed line in FIG. 1, they release the sheet end and a second group of suction cups, suction rollers or the like (not shown for the sake of clarity) moving in the opposite direction to the first group of suction cups, attach themselves to the end of the next sheet. The two groups of suction cups or suction rollers are coupled so that one group moves to the right while the other group is drawn to the left by the sheet. The control of the suction cups 2 by each adhering sheet can be replaced by a mechanical control means which move the suction cups at the speed of belts g.

As indicated by a second larger arrowed line, the rollers f and h are horizontally adjustable so that they can be adapted to the length of the sheets being processed. The distance between these rollers and the rollers d is substantially equal to the length to which the sheets are being cut.

The sequence of underlapping sheets travelling on the belts g and between rollersfand 11 passes onto conveyor belts i which convey the underlapping sheets as far as the head stop or abutment k, which arrests the uppermost and leading sheet. This sheet is then engaged by suction cups 1 at its left-hand longitudinal edge (as seen in FIG. 2) and is fed transversely of its previous direction of movement to rollers m of a feed table n which feed the sheets to a machine t in which they are further processed.

In order that the underlapping sheets can be smoothly pushed together without disturbance when they come into contact with the head stop or abutment k, even when thin sheets are being processed, parallel rails r (FIG. 3) are arranged beneath the belts i and are individually vertically adjustable by rotation of shaft s. As shown in FIG. 4, the rails r can thus be adjusted to give a slight transverse curvature to the sheets. As a result, the sheets are stiffened and creasing is prevented.

To enable the feeder means to be used without appreciable conversion and in a very short space of time for feeding cut sheets which are fed conventionally by means of a raisable pile table, as shown in FIG. 5, the belts i are mounted with their end rollers on their own frame 0 which allows these conveyor belts to be lowered and laterally withdrawn. By turning crank p, the bell crank lever u, which supports one end of the frame 0 on the horizontal rail, is turned upwards. In this way the conveyor belt 1' and the head stop or abutment k are lowered into a position whereby the frame 0 together with the belts i can be pushed beneath belts c and g. A vertically adjustable pile table u carrying a pile of sheets q can be readily moved into position in the resulting free space.

I claim:

1. Apparatus for feeding sheets of paper cut from a continuous web of paper in an underlapping sequence comprising first conveyor means, second conveyor edge of said first sheet is moved by said second conveying means to stretch the first sheet and allow the leading edge of a following second sheet to be moved beneath the lifted trailing edge of said first sheet, said suction retarding means being released from said first sheet at the end of said predetermined distance. 

1. Apparatus for feeding sheets of paper cut from a continuous web of paper in an underlapping sequence comprising first conveyor means, second conveyor means which run at a speed less than the speed of said first conveyor means, suction retarding means disposed above the conveying path and between the first and second conveying means for lifting and attaching to the trailing edge of a first sheet and moving with said first sheet a predetermined distance parallel to the line of travel of said first sheet at a speed less than that of said first conveyor means at the same time that the leading edge of said first sheet is moved by said second conveying means to stretch the first sheet and allow the leading edge of a following second sheet to be moved beneath the lifted trailing edge of said first sheet, said suction retarding means being released from said first sheet at the end of said predetermined distance. 